Idler roller drive for continuous web feeds



Nov. 7, 1950 P. CHERIGIE IDLER ROLLER DRIVE- FOR CONTINUOUS WEB FEEDS Filed Jan. 4, 1950 XNVENTOR P/EERE CHEF/6A6 ORNEY Patented Nov. 7, 1950 IDLER ROLLER DRIVE FOR .GONTINUOUS WEB FEEDS Pierre Cherigi, Paris, France, assig'norto 'La Cellophane, Paris, France, .a French company Application January 4, 1950, Serial No. 136,811 In France January 12, 1949 This invention relates to a drive for idler rollers such as are used to guide continuous webs through treating or processing zones and is particularly adapted for use with webs of low tensile strength such as webs of regenerated cellulose or other hydrophilic materials.

An-objectis to provide a drive of the above type which reduces or eliminates'the strain on the web during the starting and running periods of the machine. 7

Another object is to provide a continuous semipositive drive together with a substantially free running starting device to assist in the starting of the rollers.

Another object is to provide a dependable and efficient drive of the type above indicated.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

Continuous webs are commonly dried in a drier provided with the usual devices for admitting hot air and exhausting air charged with moisture, in which the web is guided by rollers to keep it flat and to confine its path to a limited space.

In the course of drying. the web may undergo a change of length, usually due to more or less shrinkage, especially in the case of hydrophilic webs such as regenerated cellulose film. It is necessary that the speeds of the successive rollers correspond to the speed of the web. In one type of known device the web is guided by positively driven rollers at the inlet and outlet ends of the drier, while the intermediate guide rollers are idle and driven by the web. To ensure ease of rotation, these rollers are mounted on ball bearings or the like. However, in order to prevent subjecting the web to excessive tensions which may cause breakage especially due to the inertia of the rollers when the drier is started, it has been previously proposed that the rollers be provided with a semi-positive friction drive. For this purpose the shaft of each roller is provided with an idler pulley on ball bearings. This pulley has a lateral spring bracket near its edge which frictionally drives the roller. All of these idler pulleys are aligned and driven, when the drier is in operation, by a belt which also serves to drive the feed rollers. This belt runs constantly and under very adverse conditions, that is in a hot and very moist atmosphere. It is subject to frequent failure requiring stoppage of the drier, with consequent stoppage of the entire casting and treating machine preceding it, with resulting loss of production.

The present invention provides an improved 3 Claims. (01. 74- 665) -failurei in normal operations.

roller .drive which eliminates the above disadvantages of previous drives. In one embodiment the roller is mounted on ball bearings for free rotation and issemi-positively driven during operationby a bracket fixed to a gear driven from the-main drive and revolving on the roller shaft on bail bearings.v The ball bearings may of course :be replaced ebyzrolleribearings, needle bearings, etc. The gear is located outside thehousing of the drier, and there is no .risk .of operating The starting of the web when thedrier is put This belt normally has drier is in operation.

The drive pursuant to the present invention is particularly advantageous in the casting, treating and drying, by a continuous process, of regenerated cellulose films at over meters per minute, e. g. or more meters per minute, where devices with ordinary idler rollers have proved totally inadequate and where the known device previously described causes frequent stoppages due to failure of the belt.

One embodiment of the invention is shown in the accompanying drawing in which the figure is an axial section through an idler roller showing the present drive.

In the drawing, the idler roller I has two .hubs 2 and 3 revolving in ball bearings 4 and 5 mounted on the frame F of the drier. Between bearing 4 and roller I, the hub 2 carries an idler pulley 6 mounted by ball bearings 1 on hub 2, and driven by a starting belt 8 which also passes over the pulleys of all of the other idler rollers in the drier (not shown).

The hub 3 outside the housing F of the drier carries a gear 9 on a ball bearing 10, which is driven by the main drive transmission of the drier (not shown). This gear'9, near its periphery, carries a lateral finger H with friction shoe l2 contacting the flange l3 of a cup [4 attached to the hub 3. The roller I is thus driven by friction, and its speed will adapt, with more or less slippage, to the speed of the web being dried.

During starting the belt 8 is driven by suitable means and in turn drives the pulley 6 which rotates on the bearings l on the hub 2 of the roller i. The bearings I exert a friction drag on the hub which applies a starting torque sufiicient to assist the gear 9 in bringing the roller gradually to running speed. When the roller has reached running speed the drive of the belt 8 is stopped and the pulley 6 remains stationary.

Since the belt 8 is only driven during starting the likelihood of failure is reduced. The main semi-positive friction drive due to the pad [2 acting on the cup I3 is located outside of the drier and is not subjected to the moist atmosphere therein. Hence its action is uniform and dependable and can be readily observed.

Although the device described has been specifically designed for the drying of webs of hydrophilic film, such as regenerated cellulose, it may likewise be used for the drying of other continu--' It may also be adapted to drive rollers in treating vats for hydrophilic films, especially where the film undergoes a change in length, or to drive a roller stretcher.

What is claimed is:

1. A drive for idler rollers for guiding continuous webs through a treating zone, comprising a roller having 'hubs extending axially therefrom, bearings supporting said hubs for, free rotation, a driven'gear journalledlon one of said hubs for free rotation, a member attached to said hub and having an annular friction driving surface, a friction member carried by said gear and engaging said surface to provide a semi-positive friction drive for said roller, a pulley journalled on one of said hubs for free rotation thereon, and means driving said pulley during acceleration periods only for applying a torque to said hub due to the friction of the pulley mounting to aid in starting the roller. 7

2. A drive for idler rollers for guiding continuous webs through a treating zone, comprising a roller having hubs extending axially therefrom, bearings supporting said hubs for free rotation, a driven gear journalled on one of said hubs for free rotation, a member attached to said hub and having an annular friction driving surface, a friction member carried by said gear and engaging said surface to provide a semi-positive friction drive for said roller, a pulley journalled on ball bearings on one of said hubs for free rotation therein, and means driving said pulley during acceleration periods only for applying a torque to said hub due to the friction of the pulley mounting to aid in starting the roller.

3. In a drier having a housing and idler rollers to guide a web therethrough, a drive for said idler rollers, comprising a roller having hubs extending axially therefrom, bearings in said housing supporting said hubs for free rotation, a driven gear journalled on one of said hubs outside of said housing for free rotation, a member attached to said hub and having an annular friction driving surface, a friction member carried by said gear and engaging said surface to provide a semipositive friction drive for said roller, a pulley journalled on one of said hubs inside of said housing for free rotation therein and a belt in said housing driving said pulley during acceleration periods only for applying a torque to said hub due to the friction of the pulley mounting to aid in starting said roller. 7

PIERRE CHERIGIE.

No references cited. 

